Some print cartridges include multiple dies. Each die includes thousands of nozzles that deposit ink upon media.
Due to manufacturing variations, ink chemistry, and environmental effects of temperature and humidity on the printing process, the ink discharged from these dies can vary. For example, ink drop weight produced by different print heads often varies as a result of minute manufacturing differences in the size of the nozzles used in an inkjet print head, different resistor characteristics in the heater element used to eject the ink droplets in the inkjet print head, variations in the orifice shape, or any other difference from one print head to another. Differences in the ink chemistry combined with temperature and humidity also affect the final color appearance when applied to a print medium.
If corrections are not made for these differences, visible print quality defects are introduced on the media. Since the print swaths of the individual die are immediately adjacent each other, such defects are readily discernible, particularly when attempting to reproduce high quality graphics and images. For example, banding or non-uniformity can occur on printed photographs.